1. Field
Apparatuses consistent with the inventive concept relate to a display apparatus, and more particularly, to a structure that fixes a light guide plate (LGP) and an optical sheet in a backlight unit (BLU) of a display apparatus.
2. Description of the Related Art
Display apparatuses employing thin-film transistor liquid crystal display (TFT-LCD) panels require backlight units (BLUs) to display images. Generally, cold cathode fluorescent lamps (CCFLs) are widely used as light sources of BLUs. However, recently, CCFLs are being replaced with light emitting diodes (LEDs) as a result of restriction on use of mercury and an increase in demand for slimmer display apparatuses.
BLUs may be edge-type BLUs or direct-lighting type BLUs according to the location of LEDs used as light sources of BLUs. In the case of an edge-type BLU, a light source is disposed around a light guide plate (LGP) corresponding to a frame of the BLU, and an optical sheet is disposed on a rear surface of the LGP in order to uniformly diffuse light of the light source passing through the LGP to equalize brightness of the LGP.
The LGP is fixed and separated from the light source by a predetermined distance to prevent the LGP which is made of resin materials from being thermally deformed by heat generated by lighting the LED. In order to fix the LGP, the LGP includes a plurality of fixing projections such as studs which are disposed at regular intervals on a housing of a display apparatus, and a plurality of support grooves into which the plurality of fixing projections are inserted. Accordingly, the LGP may be fixed by connection of the fixing projections and the support grooves. The fixing projections are sufficiently thick to support the weight of the LGP. Additionally, the support grooves are disposed to correspond to the fixing projections or at appropriate intervals, based on an amount of the LGP to be constricted, expanded or dropped down.
Additionally, the optical sheet needs to be attached to the LGP. The optical sheet has a predetermined pattern formed thereon to enable the light of the LED transmitted through the LGP to be appropriately diffused, so that a constant brightness of the LGP may be maintained. However, if the optical sheet is moved, a light leakage phenomenon may occur, so there is a need to accurately fix the optical sheet in an appropriate position. Accordingly, the optical sheet requires a plurality of openings, so as to be hung on a sheet hanger connected to the housing of the display apparatus.
Considering characteristics of edge-type BLUs, the fixing projections and sheet hanger need to be disposed proximate the light source. However, in this situation, grooves need to be formed on a portion of the LGP which faces the fixing projections and sheet hanger, so that the fixing projections and sheet hanger may pass through the grooves. Accordingly, it is impossible to avoid loss of light in the portion where the grooves are formed. Therefore, there is a need to carefully take into consideration the mounting location, the size and the number of fixing projections and sheet hanger.